Fatigue Damage Analysis of the Straight Switch Rail Considering Complex Random Loads

It is of particular importance to be able to properly describe the complex alternating loads on a high-speed turnout, in order to accurately analyse fatigue damage and predict the fatigue life of the overall turnout structure. To this end, a vehicle-turnout rigid-flexible coupling dynamics model that considers the randomness of actual vehicle parameters and track conditions was built for this paper. The load-time history of turnout rails was traced under random conditions to systematically analyze the actual change in load characteristics on the straight switch rail. Finally, the fatigue damage and life of the straight switch rail were predicted based on the Multi-load step stress analysis, S-N curve and Miner's principle of damage accumulation. The results showed that complex random excitation caused a change in load sequence on the straight switch rail, while the fatigue-sensitive area extended backwards to the cross-sections with a top width of 45-55 mm. The severest fatigue damage was observed on the cross-section of the straight switch rail with a top width of 50 mm. The result remains the same as the fatigue damage zone of the on-site straight switch rail, which verifies the accuracy of the calculation.